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<p>ES6&#x6807;&#x51C6;&#x65B0;&#x589E;&#x4E86;&#x4E00;&#x79CD;&#x65B0;&#x7684;&#x51FD;&#x6570;&#xFF1A;Arrow Function&#xFF08;&#x7BAD;&#x5934;&#x51FD;&#x6570;&#xFF09;&#x3002;</p>
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<pre><code class="lang-javascript"><span class="hljs-function"><span class="hljs-keyword">function</span> (<span class="hljs-params">x</span>) </span>{
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<pre><code class="lang-javascript"><span class="hljs-keyword">const</span> pow = x =&gt; x * x;
<span class="hljs-built_in">console</span>.log(pow(<span class="hljs-number">2</span>)); <span class="hljs-comment">// 4</span>
</code></pre>
<p>&#x7BAD;&#x5934;&#x51FD;&#x6570;&#x76F8;&#x5F53;&#x4E8E;&#x533F;&#x540D;&#x51FD;&#x6570;&#xFF0C;&#x5E76;&#x4E14;&#x7B80;&#x5316;&#x4E86;&#x51FD;&#x6570;&#x5B9A;&#x4E49;&#x3002;&#x7BAD;&#x5934;&#x51FD;&#x6570;&#x6709;&#x4E24;&#x79CD;&#x683C;&#x5F0F;&#xFF0C;&#x4E00;&#x79CD;&#x50CF;&#x4E0A;&#x9762;&#x7684;&#xFF0C;&#x53EA;&#x5305;&#x542B;&#x4E00;&#x4E2A;&#x8868;&#x8FBE;&#x5F0F;&#xFF0C;&#x8FDE;<code>{ ... }</code>&#x548C;<code>return</code>&#x90FD;&#x7701;&#x7565;&#x6389;&#x4E86;&#x3002;&#x8FD8;&#x6709;&#x4E00;&#x79CD;&#x53EF;&#x4EE5;&#x5305;&#x542B;&#x591A;&#x6761;&#x8BED;&#x53E5;&#xFF0C;&#x8FD9;&#x65F6;&#x5019;&#x5C31;&#x4E0D;&#x80FD;&#x7701;&#x7565;<code>{ ... }</code>&#x548C;<code>return</code></p>
<p>&#x5982;&#x679C;&#x53C2;&#x6570;&#x4E0D;&#x662F;&#x4E00;&#x4E2A;&#xFF0C;&#x5C31;&#x9700;&#x8981;&#x7528;&#x62EC;&#x53F7;<code>()</code>&#x62EC;&#x8D77;&#x6765;&#xFF1A;</p>
<pre><code class="lang-javascript"><span class="hljs-comment">// &#x4E24;&#x4E2A;&#x53C2;&#x6570;:</span>
(x, y) =&gt; x * x + y * y

<span class="hljs-comment">// &#x65E0;&#x53C2;&#x6570;:</span>
() =&gt; <span class="hljs-number">3.14</span>

<span class="hljs-comment">// &#x53EF;&#x53D8;&#x53C2;&#x6570;:</span>
(x, y, ...rest) =&gt; {
    <span class="hljs-keyword">var</span> i, sum = x + y;
    <span class="hljs-keyword">for</span> (i=<span class="hljs-number">0</span>; i&lt;rest.length; i++) {
        sum += rest[i];
    }
    <span class="hljs-keyword">return</span> sum;
}
</code></pre>
<p>&#x5982;&#x679C;&#x8981;&#x8FD4;&#x56DE;&#x4E00;&#x4E2A;&#x5BF9;&#x8C61;&#xFF0C;&#x5C31;&#x8981;&#x6CE8;&#x610F;&#xFF0C;&#x5982;&#x679C;&#x662F;&#x5355;&#x8868;&#x8FBE;&#x5F0F;&#xFF0C;&#x8FD9;&#x4E48;&#x5199;&#x7684;&#x8BDD;&#x4F1A;&#x62A5;&#x9519;&#xFF1A;</p>
<pre><code class="lang-javascript"><span class="hljs-comment">// SyntaxError:</span>
x =&gt; { foo: x }
</code></pre>
<p>&#x56E0;&#x4E3A;&#x548C;&#x51FD;&#x6570;&#x4F53;&#x7684;<code>{ ... }</code>&#x6709;&#x8BED;&#x6CD5;&#x51B2;&#x7A81;&#xFF0C;&#x6240;&#x4EE5;&#x8981;&#x6539;&#x4E3A;&#xFF1A;</p>
<pre><code class="lang-javascript"><span class="hljs-comment">// ok:</span>
x =&gt; ({ foo: x })
</code></pre>
<h3 id="this">this</h3>
<p>&#x7BAD;&#x5934;&#x51FD;&#x6570;&#x770B;&#x4E0A;&#x53BB;&#x662F;&#x533F;&#x540D;&#x51FD;&#x6570;&#x7684;&#x4E00;&#x79CD;&#x7B80;&#x5199;&#xFF0C;&#x4F46;&#x5B9E;&#x9645;&#x4E0A;&#xFF0C;&#x7BAD;&#x5934;&#x51FD;&#x6570;&#x548C;&#x533F;&#x540D;&#x51FD;&#x6570;&#x6709;&#x4E2A;&#x660E;&#x663E;&#x7684;&#x533A;&#x522B;&#xFF1A;&#x7BAD;&#x5934;&#x51FD;&#x6570;&#x5185;&#x90E8;&#x7684;<code>this</code>&#x662F;&#x8BCD;&#x6CD5;&#x4F5C;&#x7528;&#x57DF;&#xFF0C;&#x7531;&#x4E0A;&#x4E0B;&#x6587;&#x786E;&#x5B9A;&#x3002;</p>
<p><code>this</code>&#x6307;&#x5411;&#x7684;&#x56FA;&#x5B9A;&#x5316;&#xFF0C;&#x5E76;&#x4E0D;&#x662F;&#x56E0;&#x4E3A;&#x7BAD;&#x5934;&#x51FD;&#x6570;&#x5185;&#x90E8;&#x6709;&#x7ED1;&#x5B9A;<code>this</code>&#x7684;&#x673A;&#x5236;&#xFF0C;&#x5B9E;&#x9645;&#x539F;&#x56E0;&#x662F;&#x7BAD;&#x5934;&#x51FD;&#x6570;&#x6839;&#x672C;&#x6CA1;&#x6709;&#x81EA;&#x5DF1;&#x7684;<code>this</code>&#xFF0C;&#x5BFC;&#x81F4;&#x5185;&#x90E8;&#x7684;<code>this</code>&#x5C31;&#x662F;&#x5916;&#x5C42;&#x4EE3;&#x7801;&#x5757;&#x7684;<code>this</code>&#x3002;&#x6B63;&#x662F;&#x56E0;&#x4E3A;&#x5B83;&#x6CA1;&#x6709;<code>this</code>&#xFF0C;&#x6240;&#x4EE5;&#x4E5F;&#x5C31;&#x4E0D;&#x80FD;&#x7528;&#x4F5C;&#x6784;&#x9020;&#x51FD;&#x6570;&#x3002;</p>
<pre><code class="lang-javascript"><span class="hljs-keyword">var</span> obj = {
    birth: <span class="hljs-number">1990</span>,
    getAge: <span class="hljs-function"><span class="hljs-keyword">function</span> (<span class="hljs-params">year</span>) </span>{
        <span class="hljs-keyword">var</span> b = <span class="hljs-keyword">this</span>.birth; <span class="hljs-comment">// 1990</span>
        <span class="hljs-keyword">var</span> fn = (y) =&gt; y - <span class="hljs-keyword">this</span>.birth; <span class="hljs-comment">// this.birth&#x4ECD;&#x662F;1990</span>
        <span class="hljs-keyword">return</span> fn.call({birth:<span class="hljs-number">2000</span>}, year);
    }
};
obj.getAge(<span class="hljs-number">2015</span>); <span class="hljs-comment">// 25</span>
</code></pre>
<p>&#x8BF7;&#x95EE;&#x4E0B;&#x9762;&#x7684;&#x4EE3;&#x7801;&#x4E4B;&#x4E2D;&#x6709;&#x51E0;&#x4E2A;<code>this</code>&#xFF1F;</p>
<pre><code class="lang-javascript"><span class="hljs-function"><span class="hljs-keyword">function</span> <span class="hljs-title">foo</span>(<span class="hljs-params"></span>) </span>{
  <span class="hljs-keyword">return</span> () =&gt; {
    <span class="hljs-keyword">return</span> () =&gt; {
      <span class="hljs-keyword">return</span> () =&gt; {
        <span class="hljs-built_in">console</span>.log(<span class="hljs-string">&apos;id:&apos;</span>, <span class="hljs-keyword">this</span>.id);
      };
    };
  };
}

<span class="hljs-keyword">var</span> f = foo.call({id: <span class="hljs-number">1</span>});

<span class="hljs-keyword">var</span> t1 = f.call({id: <span class="hljs-number">2</span>})()(); <span class="hljs-comment">// id: 1</span>
<span class="hljs-keyword">var</span> t2 = f().call({id: <span class="hljs-number">3</span>})(); <span class="hljs-comment">// id: 1</span>
<span class="hljs-keyword">var</span> t3 = f()().call({id: <span class="hljs-number">4</span>}); <span class="hljs-comment">// id: 1</span>
</code></pre>
<p>&#x4E0A;&#x9762;&#x4EE3;&#x7801;&#x4E4B;&#x4E2D;&#xFF0C;&#x53EA;&#x6709;&#x4E00;&#x4E2A;<code>this</code>&#xFF0C;&#x5C31;&#x662F;&#x51FD;&#x6570;<code>foo</code>&#x7684;<code>this</code>&#xFF0C;&#x6240;&#x4EE5;<code>t1</code>&#x3001;<code>t2</code>&#x3001;<code>t3</code>&#x90FD;&#x8F93;&#x51FA;&#x540C;&#x6837;&#x7684;&#x7ED3;&#x679C;&#x3002;&#x56E0;&#x4E3A;&#x6240;&#x6709;&#x7684;&#x5185;&#x5C42;&#x51FD;&#x6570;&#x90FD;&#x662F;&#x7BAD;&#x5934;&#x51FD;&#x6570;&#xFF0C;&#x90FD;&#x6CA1;&#x6709;&#x81EA;&#x5DF1;&#x7684;<code>this</code>&#xFF0C;&#x5B83;&#x4EEC;&#x7684;<code>this</code>&#x5176;&#x5B9E;&#x90FD;&#x662F;&#x6700;&#x5916;&#x5C42;<code>foo</code>&#x51FD;&#x6570;&#x7684;<code>this</code>&#x3002;</p>
<p>&#x9664;&#x4E86;<code>this</code>&#xFF0C;&#x4EE5;&#x4E0B;&#x4E09;&#x4E2A;&#x53D8;&#x91CF;&#x5728;&#x7BAD;&#x5934;&#x51FD;&#x6570;&#x4E4B;&#x4E2D;&#x4E5F;&#x662F;&#x4E0D;&#x5B58;&#x5728;&#x7684;&#xFF0C;&#x6307;&#x5411;&#x5916;&#x5C42;&#x51FD;&#x6570;&#x7684;&#x5BF9;&#x5E94;&#x53D8;&#x91CF;&#xFF1A;<code>arguments</code>&#x3001;<code>super</code>&#x3001;<code>new.target</code>&#x3002;</p>
<pre><code class="lang-javascript"><span class="hljs-function"><span class="hljs-keyword">function</span> <span class="hljs-title">foo</span>(<span class="hljs-params"></span>) </span>{
  setTimeout(() =&gt; {
    <span class="hljs-built_in">console</span>.log(<span class="hljs-string">&apos;args:&apos;</span>, <span class="hljs-built_in">arguments</span>);
  }, <span class="hljs-number">100</span>);
}

foo(<span class="hljs-number">2</span>, <span class="hljs-number">4</span>, <span class="hljs-number">6</span>, <span class="hljs-number">8</span>)
<span class="hljs-comment">// args: [2, 4, 6, 8]</span>
</code></pre>
<p>&#x4E0A;&#x9762;&#x4EE3;&#x7801;&#x4E2D;&#xFF0C;&#x7BAD;&#x5934;&#x51FD;&#x6570;&#x5185;&#x90E8;&#x7684;&#x53D8;&#x91CF;<code>arguments</code>&#xFF0C;&#x5176;&#x5B9E;&#x662F;&#x51FD;&#x6570;<code>foo</code>&#x7684;<code>arguments</code>&#x53D8;&#x91CF;&#x3002;</p>
<h3 id="&#x4FBF;&#x5229;">&#x4FBF;&#x5229;</h3>
<p>&#x5982;&#xFF0C;&#x4E4B;&#x524D;&#x7684;&#x6392;&#x5E8F;&#x53EF;&#x4EE5;&#xFF1A;</p>
<pre><code class="lang-javascript"><span class="hljs-keyword">let</span> arr = [<span class="hljs-number">10</span>,<span class="hljs-number">20</span>,<span class="hljs-number">1</span>,<span class="hljs-number">2</span>];
arr.sort((x,y)=&gt;x-y);
</code></pre>
<h3 id="&#x4E0D;&#x9002;&#x7528;&#x573A;&#x5408;">&#x4E0D;&#x9002;&#x7528;&#x573A;&#x5408;</h3>
<p>&#x7531;&#x4E8E;&#x7BAD;&#x5934;&#x51FD;&#x6570;&#x4F7F;&#x5F97;<code>this</code>&#x4ECE;&#x201C;&#x52A8;&#x6001;&#x201D;&#x53D8;&#x6210;&#x201C;&#x9759;&#x6001;&#x201D;&#xFF0C;&#x4E0B;&#x9762;&#x4E24;&#x4E2A;&#x573A;&#x5408;&#x4E0D;&#x5E94;&#x8BE5;&#x4F7F;&#x7528;&#x7BAD;&#x5934;&#x51FD;&#x6570;&#x3002;</p>
<p>&#x7B2C;&#x4E00;&#x4E2A;&#x573A;&#x5408;&#x662F;&#x5B9A;&#x4E49;&#x5BF9;&#x8C61;&#x7684;&#x65B9;&#x6CD5;&#xFF0C;&#x4E14;&#x8BE5;&#x65B9;&#x6CD5;&#x5185;&#x90E8;&#x5305;&#x62EC;<code>this</code>&#x3002;</p>
<pre><code class="lang-javascript"><span class="hljs-keyword">const</span> cat = {
  lives: <span class="hljs-number">9</span>,
  jumps: () =&gt; {
    <span class="hljs-keyword">this</span>.lives--;
  }
}
</code></pre>
<p>&#x4E0A;&#x9762;&#x4EE3;&#x7801;&#x4E2D;&#xFF0C;<code>cat.jumps()</code>&#x65B9;&#x6CD5;&#x662F;&#x4E00;&#x4E2A;&#x7BAD;&#x5934;&#x51FD;&#x6570;&#xFF0C;&#x8FD9;&#x662F;&#x9519;&#x8BEF;&#x7684;&#x3002;&#x8C03;&#x7528;<code>cat.jumps()</code>&#x65F6;&#xFF0C;&#x5982;&#x679C;&#x662F;&#x666E;&#x901A;&#x51FD;&#x6570;&#xFF0C;&#x8BE5;&#x65B9;&#x6CD5;&#x5185;&#x90E8;&#x7684;<code>this</code>&#x6307;&#x5411;<code>cat</code>&#xFF1B;&#x5982;&#x679C;&#x5199;&#x6210;&#x4E0A;&#x9762;&#x90A3;&#x6837;&#x7684;&#x7BAD;&#x5934;&#x51FD;&#x6570;&#xFF0C;&#x4F7F;&#x5F97;<code>this</code>&#x6307;&#x5411;&#x5168;&#x5C40;&#x5BF9;&#x8C61;&#xFF0C;&#x56E0;&#x6B64;&#x4E0D;&#x4F1A;&#x5F97;&#x5230;&#x9884;&#x671F;&#x7ED3;&#x679C;&#x3002;<font color="orange">&#x8FD9;&#x662F;&#x56E0;&#x4E3A;&#x5BF9;&#x8C61;&#x4E0D;&#x6784;&#x6210;&#x5355;&#x72EC;&#x7684;&#x4F5C;&#x7528;&#x57DF;</font>&#xFF0C;&#x5BFC;&#x81F4;<code>jumps</code>&#x7BAD;&#x5934;&#x51FD;&#x6570;&#x5B9A;&#x4E49;&#x65F6;&#x7684;&#x4F5C;&#x7528;&#x57DF;&#x5C31;&#x662F;&#x5168;&#x5C40;&#x4F5C;&#x7528;&#x57DF;&#x3002;</p>
<p>&#x7B2C;&#x4E8C;&#x4E2A;&#x573A;&#x5408;&#x662F;&#x9700;&#x8981;&#x52A8;&#x6001;<code>this</code>&#x7684;&#x65F6;&#x5019;&#xFF0C;&#x4E5F;&#x4E0D;&#x5E94;&#x4F7F;&#x7528;&#x7BAD;&#x5934;&#x51FD;&#x6570;&#x3002;</p>
<pre><code class="lang-javascript"><span class="hljs-keyword">var</span> button = <span class="hljs-built_in">document</span>.getElementById(<span class="hljs-string">&apos;press&apos;</span>);
button.addEventListener(<span class="hljs-string">&apos;click&apos;</span>, () =&gt; {
  <span class="hljs-keyword">this</span>.classList.toggle(<span class="hljs-string">&apos;on&apos;</span>);
});
</code></pre>
<p>&#x4E0A;&#x9762;&#x4EE3;&#x7801;&#x8FD0;&#x884C;&#x65F6;&#xFF0C;&#x70B9;&#x51FB;&#x6309;&#x94AE;&#x4F1A;&#x62A5;&#x9519;&#xFF0C;&#x56E0;&#x4E3A;<code>button</code>&#x7684;&#x76D1;&#x542C;&#x51FD;&#x6570;&#x662F;&#x4E00;&#x4E2A;&#x7BAD;&#x5934;&#x51FD;&#x6570;&#xFF0C;&#x5BFC;&#x81F4;&#x91CC;&#x9762;&#x7684;<code>this</code>&#x5C31;&#x662F;&#x5168;&#x5C40;&#x5BF9;&#x8C61;&#x3002;&#x5982;&#x679C;&#x6539;&#x6210;&#x666E;&#x901A;&#x51FD;&#x6570;&#xFF0C;<code>this</code>&#x5C31;&#x4F1A;&#x52A8;&#x6001;&#x6307;&#x5411;&#x88AB;&#x70B9;&#x51FB;&#x7684;&#x6309;&#x94AE;&#x5BF9;&#x8C61;&#x3002;</p>

                                
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